The present invention relates to a bow seal for a surface effect ship.
Surface effect ships, also known as gas cushion vehicles, are supported, at least in part, by a cushion of pressurized gas formed and contained between the vehicle body and the surface water. As these vehicles operate over turbulent water surfaces, they encounter waves which exert substantial forces on the vehicle body. These waves can be so powerful that heavy damage may be inflicted on the craft.
The new generation of boats are required to operate at speeds in the vicinity of 80-100 knots. Since the sidewalls are thin, they cannot develop such bouyant lift when entering a wave. Thus, the wave is swallowed by the ship causing the bow seal to move up the height of the wave or by plowing a trough in the wave as the ship passes through. The action of the present flat plate type seal induces high acceleration and their resultant loads on the ships. These forces could conceivably be much in excess of the habitability limits.
The instant invention is designed to penetrate the wave as a conventional boat bow does, and at the same time lift up to allow the seal trailing edge to ride over the wave; the horizontal and vertical acceleration forces could be reduced, and this would then permit higher speeds within the habitability limits. The keels of the prior art, by contrast, are made of hinged plates which are exposed to the entire wave shock and transfer the full acceleration thereof into the boat.
A roller is provided at the aft end of the keel with the function being the reduction of drag of the bow and stern seals.